Combined telephone and fire-alarm or kindred service system.



W. W. DEAN. COMBINED TELEPHONE AND FIRE ALARM 0B. KINDRBD SERVICE SYSTEM.

APPLICATION FILED AUG. 15. 1903.

Patented Apr. 12, 1910.

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j UNITED STATES PATENT orr on.

WILLIAM w. DEAN, or CHICAGO, ILL'I oIs, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 CONSOLIDATED FIRE ALARM COMPANY, on NEW YORK, N. Y A CORPORATION OF NEW YORK.

CQMBINED TELEPHONE AND FIRE-ALARM OR KINDRED- SERVICE; SYSTEM."

Specification of Letters Patent.

Application filed August 15, 1903. Serial No. 169,558. l

To all whom iii may concern.

Be it known that I, WILLIAM lVQ-DEAN, a citizen of the United States of America, and resident of Chicago, county of Cook, and State of Illinois, have invented a new and useful Improvement in Combined Telephone and Fire-Alarm or Kindred Service Systems, of which the following is a specification.

My invention relates to fire and kindred alarm service as applied to telephone exchanges, my object being to provide a system in which the currents used in the alarm service do not normally afiect the telephone apparatus and which likewise the currents employed for telephonic purposes do not afiect the alarm service.

In the ordinary type of telephone system in which a common sourceof current at the central otfice is employed for conversation, trouble is experienced in engrafting'thereupon an auxiliary alarm service due to the fact that ground connections and live bat tery connections are present at dilferent points and in different ways upon the lines and circuits of the telephone exchange.

In carrying out my invention -I prefer to use for the auxiliary service high frequency signaling currents which do not cause the operation of the telephone apparatus normally associated with the lines and an alarm receiving apparatus at. the central office which is responsive to such high frequency currents but is unresponsive to the telephone signaling and talking currents. Again, it is desirable in any fire alarm, messenger call, telephonic or other similar electrical installations in buildings, to dispense with vall ground connections for the active operation of electrical apparatus, since such connections are not subject. to a constant test as to their working condition. In my invention I also seek to avoid all ground connections outside of the central station, and to operate said alarm'system' over the metallic circuit whereby all objections of the kind mentioned are avoided.

My invention is illustrated in the acco1n-' panying drawings in Which-- Figure l is a diagram of a system showing 'one manner of applying the invention to a telephone exchange; Fig. 2 is a diagram of a modification, and Fig. 3 1s a diagram ct still another modification.

In Fig. l, L indicates a telephoneline. ex

tending in two limbs "2 and 3 fro1n.the, s11b scribers station to the central office? At the subscribers station, the usual: call bell land condenser 5 are included in, a permanent.

bridge of the line conductora whi'le a-transmitter 6 and receiver? are located n a second bridge, which is normally open at the the telephone line. The line conductor 3 is normally connected through contacts of said cut-otf'relay with a conductor 9 leading to the line relay R whose other terminal is.

joined to the common lead 10 ,extendinglto the live pole of the central and commonbattery B. The said line relay R controls thelocal circuit of the line signal Stand thecut off relay R hasits winding grounded from the sleeve conductor of the jack, section vof the telephone line with which said, line conwiththe tip conductor of the jack section of Patented Apr; 12, 1910.

ductor 3 is connected when the ci'it ofi' rem,"

connected at the same, line signal inoperative.

Thefcord circuitsare of th llsualyltylle and each includes an answering plug P; and

is energized, saidline relay'lR 'beiug distime to rendei the.

sponding contacts of the spring-jacks of the telephone line, the said tip contacts be ing connected by the fiexiblestrands hand 25 and the condenser 0:, while the sleeve: contacts are similarly joined by sti ands 8 and s and the interposedoondenser 0?. l. p ei visory relays 1 and 1' are connected across the answering end of the cord circuit upon opposite sides of the battery B and together control the local circuit of the superv sory signal S associated with the answering plug. 7, P, while supervisory relays, 95* :and r are similarly connected across the calling end 01; the cord circuit upon either side of a second common battery B and control the local circuit of supervisory signaltS asso ciated'with the calling plug. In the-ordil' nary manner, the operators head telephone ioo 11, the secondary of her induction coil 12 and a suitable condenser c are adapted to be 'bridged across the calling end of the cord circuit by means of any suitable listening key, the primary of the said in- I duction coil 12 and her transmitter 13 16 including a suitable resistance 17 and the conductor 10 common to a certain number of the lines of the exchange with the live pole of, the battery B With this arrangement of the telephone line conversation may be carried on thereover in the ordinary manner, the subscriber operating his line signal by taking up his receiver and the operator answering the call by" inserting the plug P of her cord circuit in the answering jack of the telephone line. Upon learning the number of the wanted line and after determining its idle or busy condition in the usual manner, if found idle, the calling plug P is inserted in the spring jack of that line and the'ringing key springs 15 operated to ring the subscriber. The supervisory relays operate in the well known manner to independently indicate the position of the subscribers telephone and to thus keep the operator informed as to the condition of the connection.

The alarm transmitting device which may be applied at the substation of the line or at any other point thereon includes a local circuit containing a battery'B the primary winding of a rapid magnetic interrupter I, and a contact disk 18 and cooperating brush of the call alarm box. This brush rests upon an insulating segment or portion 19 of the disk 18, and serves to normally open the said local circuit. The secondary winding 20 of said interrupter I is included in a bridge of the line conductors 2 and 3, which includes also the brush and the makeand-break wheel 21 of the signaling box. It will be understood that this alarm box may be controlled in any ordinary or desired manner... and may be operated either manually as in an ordinary telegraph call box, or automatically by means of thermo stats or other devices in a local house circuit as is common in installations of this type and as is indicated in dotted lines. The armature 22 of the interrupter I is preferably a tuned reed having a high rate of vibration. As is evident, when the signaling box is operated the disks 18 and 21 rotate and the local circuit is closed through the disk 18 and its cooperating brush and the reed is started Vibrating. The rapid. make and break of this local circuit inthrough the subscribers instrument in case his receiver should be off the hook, the circuit is opened as indicated by the contact of wheel 21. At the central ofiice the said receiving apparatus includes in a bridge of the line a condenser 23 of verysmall capacity, 1/10 micro-farad having been found satisfactory, and a high resistance relay 24, say of 5000 ohms, and of high self induction bridged across the telephone line.

The capacity of the condenser and the self induction of the coil of relay 24 are preferably so adjusted that the bridge is approximately resonant to the alternating currents of the alarm system. The magnet 24 actu atesa tuned reed 25 preferably corresponding to the rate of actuation of the reed 22 at the substation. A local circuit including the magnet 26, the battery 13* and a very high resistance 27 is permanently closed,

said resistance being of substantially 5000 the conductors 29and 30. Thus under normal conditions the magnet 24 is deenergized, and the magnet 26 is likewise denergized owing to its short circuit, thus opening the circuit of the common register 28. When said magnet is actuated, however, said short circuit about the magnet 26 is opened by the reed 25, the magnet 26 is energized by current from the battery B and the local cir cuit of the register 28 is closed.

WVhen the alarm box is actuated at the substation, alternating currents of a. high frequency are sent out to the line when the contact of the disk 21 engages its teeth, and the magnet 24 is actuated, these high fre quency alarm currents being adapted to readily pass through the small capacity condenser 23 and the high resistance magnet 24. Such currents encounter retardation in the line relay R in attempting to pass over the metallic line so that the leakage in that dialarm signaling currents. Under such circumstances although the reed 25 vibrates in accordance with the high frequency currents I the short circuit of. magnet 26 will'not be closed sufiicientlythereby to'permit said magnet to be deenergized as long. as such currents are present on the line. The register 28 is adapted to register the signal upon the tape 31, the audible or visual signal 29 being also actuated.

The voice currents are prevented from passing to any great extent through" the bridge contai'iiingthe magnet 2st by reason of itsimpedance as well as on account of the weakiiessof'such Y currents, while the steady current from the battery B or B is prevented ,from passing by .the condenser 23.

This condenser is also of such small ca-' pacity that the low frequency ringing currents are likewise prevented from passing. Thus the said alarm signal mechanism remains unaffected by any'of the telephonic currents that appear on the line and in the specific arrangement shown such mechanism is not dependentfor its operation on ground connections or the source of current at the central oilice.

As shown in Fig. 2 the relay 24: may be provided with an ordinary pivoted armature 25, such relay being constructed in a manner well understood in the art, so as to respond to alternating or rapidly varying currents and thus hold up its armature when subjected to such alarm signaling currents. The register circuit may be thus directly controlled without the intermediation of relay The various batteries shown at the central office may obviously be one and the same. The alarm transmitting device need not be located close to the subscribers instrument, but may be placed anywhere upon the line as may the alarm receiving apparatus if desired. This figure also shows the make-'and-break wheel 21 and interrupter 35, preferably of the rotary type-in a bridge of the line, said interrupter being rapidly driven preferably by the'mechanism of the call box. The current from the central common battery B flowing when the wheel 21 completes the circuit thereof, i's thus broken up into shortimpulses and the condenser 23 in r the alarm bridge at central is thus charged and discharged and the magnet 24;

is operated as before described.

In Fig. 3 I show a difi'erent method of in.- ductively connecting the relay 2% to theline.

In place of the condenser of the other fig-.

ures to inductively connect the relay 2st to the line, I bridge across the circuit a winding of a transformerT, such-winding being of high enough resistance to prevent the bat tery curre t that is present on the line from undesirably operating the relays 1n the path of such current. This transformer is de.

signed to be responsive to thehigh frequency signaling currents only and not to the ringing or voice currents. These cur rents are retarded and not shunted to any disadvantageousdegree. The relay 24 is ed specifically these methods of accompli 1g the desired V results of my invention, Ido t wish .to be limited thereto in all respects "as it is obvious that broadly co'nsidered o'ther and various methods'than those shown may be employed. For example in my companion application filed August 15th, 1903 Serial No. 169,559, I showother methods of deriving and employing auxiliary signaling currents and which I intendto generically cover by my present claims.

Having thus described my invention and means for carrying the same into effect, what I claim is:

.1. In atelephone exchange, the combination with a metallic telephone line, of a subscriber-"s set at the sub-station of the line, telephonic apparatus associated with the line at the central oflice adapted to cooperate with said line and set' for conversational purposes, said apparatus including a common battery connected with the lines, an alarm signal transmitting device upon the line to send high frequency signaling currents over the two sides of the metallic telephone line in series, an alarm signal receiv ing apparatus at the central ollice including a relay of high self induction and a condenser of small capacity in a bridge of the telephone line, the self induction and capacity of said bridge being adjusted to be substantially resonant to said high frequency signaling currents, the condenser serving to prevent the passage of steady currents and low frequency alternating currents while the relay prevents the passage of the voice currents, substantially as described.

tion with a telephone line, of a subscribers set at the sub-station of the line, telephonic.

apparatus associated with the lineat the central office for cooperation with said line for conversational purposes, said apparatus including a battery connected with the line, an alarm signal transmitting device to send signaling currents of high frequency over the telephone line, an alarm signal receiving apparatus including a relay of high self induction and a condenser of small capacity in a bridge of the line, both being adjusted so as to be substantially resonant to said high frequency signaling currents, the condenser preventing the passage of steady currents and low frequency alternating currents 7 while the relay is opaque to voice currents. 3. The combination with a telephoneline of telephonic apparatus thereon, auxiliary signaling apparatus comprising an inductive vibrator with a primary supply circuitfsaid vibrator having secondary connection with the telephone line, thermally operable means controlling said signaling apparatus, and an alarm signal receiving apparatus including a relay of high self induction and a condenser of small capacity in the bridge of the line, both being adjusted so as to be substantially resonant to the high frequency currents from the vibrator, but' irresponsive to steady currents and low frequency alternating currents as well as substantially opaque to Voice currents.

l. The combination With a telephone line, of telephonic apparatus thereon, auxiliary signaling apparatus adapted to send signaling currents of high frequency over the telephone line, and an alarm signal receiving apparatus includin a relay of hi h self in- 15 duction and a con enser of smal capacity in the bridge-0f the line, both adjusted so as to be substantially resonant to the signaling currents, but impassable for steady currents or low frequency alternating currents and opaque to voice currents.

Signed by me at Chicago, county of Cook, State of Illinois, this 12th day of August WILLIAM W. DEAN.

Witnesses:

ROBERT LEWIS Arms, 4 EVA A. GARLOCK. 

